Previously studies from our laboratory have shown that Morris hepatomas differ significantly from liver with respect to their ability to convert precursor B-6 vitamer forms, such as pyridoxine, to coenzymatically active pyridoxal phosphate. For example, the rapidly growing, transplantable Morris hepatoma No. 7777 has no immunologically-detectable pyridoxine phosphate oxidase. Thus, as a consequence of transformation, this hepatoma must obtain its pyridoxal phosphate by a route(s) different from normal liver. We aim to study the uptake of radioactive B-6 vitamers by Morris hepatoma No. 7777 grown in vitro and in vivo. Cytosolic pyridoxal phosphate acquisition proteins will be labeled and characterized by SDS-PAGE methods and immunological methods involving recently developed monoclonal antibodies specific for the phosphopyridoxyl group. Another major aim is to investigate the pyridoxal phosphate binding properties of Alpha-fetoprotein, an oncodevelopmental protein which has many properties in common with albumin, a normal serum protein with a well-defined role in pyridoxal phosphate transport. A third major area of research will involve the characterization of vitamin B-6 metabolism during hepatocarcinogenesis. These studies have as their central theme the manner in which hepatomas obtain and utilize pyridoxal phosphate, a micronutrient essential to growth and development. Such studies have the potential to provide important and hitherto unavailable information on fundamental biochemical mechanisms in tumor nutrition.